News

A recently accepted publication by Heffern and coworkers in Inorganic Chemistry identifies the copper(II) and zinc(II) binding site on a peptide hormone known as C-peptide. C-peptide is made alongside insulin in the pancreas and may help with kidney and blood vessel damage in patients with diabetes. Their findings show that copper(II) and zinc(II) share the same site and compete with each other for binding at the N-terminus of the peptide.

Nano-sized galvanic replacement reaction is a powerful tool to synthesize complicate nanostructures. In this work the Kauzlarich lab (Xiao, et al., ACS Applied Nano Materials, 2020) report an unconventional galvanic replacement reaction between GeI₂ and Ag NPs with morphological and compositional control. An inward and outward diffusion mechanism is proposed and supported by imaging the different stages of the reaction and analysis of the products. The unique mechanism allows the reaction to be self-terminated and achieve nanometer-sized accuracy.

In a new JACS article (https://pubs.acs.org/doi/pdf/10.1021/jacs.0c03802), Lizhi Tao in the Britt lab works with the Tom Rauchfuss lab at Illinois and the Begley lab at Texas A&M to reveal how the radical SAM enzyme HydE activates the HydG-generated organometallic synthon [Fe(II)(CO)2CN(cysteine)] for dimerization as a key step in forming the catalytic H-cluster of Fe-Fe hydrogenase.

Thermochromic or vapochromic dyes change color in response to temperature changes or vapor pressure of organic compounds, which are useful in many applications including sensors, labels for biomaterials, thermal coatings for windows, and optoelectronic devices.  In a recent JACS publication, Lucy Luong (Balch lab) and coworkers describe experiments showed that salts of the [(C₆H₁₁NC)₂Au]⁺ cation with non-coordinating anions such as PF₆⁻, AsF₆⁻ and SbF₆⁻ feature remarkable diversity in their molecular structure, luminescence, and thermochr

The oxygen evolving complex (OEC) of photosystem II catalyzes the oxidation of water to form molecular oxygen. The S₃-state is currently the last observable intermediate prior to O–O bond formation. Its electronic structure has been assigned to a homovalent Mn(IV)₄ core with an S = 3 ground state. In a recent publication (Lee, Marchiori, et al. JACS), the Agapie (Caltech) and Britt labs synthesized and characterized via XAS and multifrequency EPR spectroscopy a Mn(IV)₄O₄ cuboidal complex.

In a new JACS article (https://pubs.acs.org/doi/10.1021/jacs.9b10273) describing a collaboration between the Britt and Gray (Caltech) labs, Sayler et al. describe a set of model materials that facilitate the understanding of individual active sites in the highly active heterogeneous water oxidation catalyst, [NiFe] LDH.  Heterogeneous catalysts often have a high magnetic density of active sites, complicating the interpretation of EPR spectroscopic data.

Thermoelectric materials have been used to provide electricity to spacecraft for decades. In this work the Kauzlarich lab (Perez, et al., ACS Appl. Energy Mater., 2020) in collaboration with Thermal Energy Conversion Research and Advancement Group at NASA-JPL have shown that Yb₁₄MgSb₁₁, one of the candidates for NASA’s next generation of thermoelectric materials, can be composited with iron without reaction upon thermal cycling.

Hydrogenases are nature’s machines to metabolize H₂. The [FeFe] hydrogenase subtype catalyzes the rapid turnover at its six-iron active site cofactor, the H-cluster, which contains CO, cyanide and a unique azadithiolate (adt) ligand essential for catalysis. In a recent publication (Rao and coworkers, Chemical Science, 2019) the Britt lab identified the biosynthetic precursor of the adt ligand.

Cesium lead iodide (CsPbI₃) has long been a promising light absorbing material for perovskite solar cells. Researchers from the Navrotsky lab, in a recently published study (J. Am. Chem. Soc. 2019, 141, 14501) conducted calorimetric studies on cubic(α) and orthorhombic(δ) CsPbI₃ polymorphs, obtaining their enthalpies of formation from binary iodides, and discussing the relative stabilities. Cubic phase CsPbI₃, the desirable phase for light absorbing material, is confirmed to be metastable under ambient conditions.

In the most recent Science, Professor R. David Britt and Chemistry PhD student David Marchiori review the latest X-ray free electron laser structure of flash generated higher oxidations states of the photosystem II oxygen evolving complex (M.